Construction of ultrafine and highly dispersed RuSe2 on WOx by “atom-to-cluster” strategy for efficient hydrogen evolution reaction

The rational design and controllable construction of efficient and stable electrocatalysts is an inevitable trend in sustainable hydrogen production. The transition metal selenides play an important role in the highly active hydrogen evolution reaction (HER) electrocatalysts. Herein, we put forward an “atom-to-cluster” strategy assisted by lacunary polyoxometalates (POMs) to successfully prepare highly dispersed RuSe2-WOx@HMCS electrocatalyst. The vacancy-directed effect of lacunary [PW9O34]9− (PW9) was utilized to anchor Ru via coordination bonds and achieve uniform dispersion of Ru at the atomic level. The uniform dispersion of the precursor Rux[PW9O34] (RuxPW9) at the molecular level was achieved by confining RuxPW9 within the mesopores of hollow mesoporous carbon spheres (HMCS). Ultrafine (≈2 nm) and highly dispersed RuSe2 on WOx was successfully produced at the cluster level by using in situ selenization. Corresponding theoretical calculations demonstrate that the secondary support WOx in combination with RuSe2 has the synergistic effect in electrocatalytic HER, responding to the significance of trivacant PW9. Meanwhile, the conductive support HMCS could promote the exposure of active sites and accelerate electron transfer. Consequently, RuSe2-WOx@HMCS exhibited excellent HER activity with overpotentials of only 58 mV and 60 mV at a current density of 10 mA∙cm−2 in 0.5 M H2SO4 and 1 M KOH solutions, respectively. This study provides a feasible “atom-to-cluster” strategy derived from POMs for the modulation and fabrication of low-cost and high-quality HER electrocatalysts.